Now residing in



i UNITED STA'IES PATENT OFFICE.

JOHN HALDEMAN, OF PHILADELPHIA, PENNSYLVANIA, NOW RESIDING IN LONDON,ENGLAND.

MODE OF HEATING PILES.

SPECIFICATION formingpart of Letters Patent No. 253,599, dated February14:, 1882. Application filcd January 12, 1882. (No specimens.) Patentedin Belgium October 30, 1880.

' To all whom it may concern Be it known that I, J OHN HALDEMAN, ofPhiladelphia, Pennsylvania, now residing in London, England, haveinvented a new Improvement in the Mode ofHeating Composite Boxes orPiles, of which the following is a specification.

The present invention relates to an improved process of heating pilescomposed of a steel core surrounded by an iron envelope in such a manneras to obtain a perfect consolidation of the two metals, and, if my modeof heating is strictly adhered to, this consolidation will be perfectinevery instance. Patents for such I 5 piles or boxes have been taken bothin the United States andEuropean countries, and my claim is confinedentirely to my mode of heating.

Experience has shown that ifcomposite piles are heated in the usualn1annerviz., by subjecting the piles only to a grad ually-increasingheat-the result would in most cases be merely an ordinary weld, as theiron would usually be brought to the proper heat before the steel wouldbe molten, or, if kept too long under such heat, the iron would burn. Inorder to produce the proposed result, I have ascertained that the twometals, differing in nature and melting at widely-differing degrees ofheat,

0 should be brought to their respective points of fusion in such amanner that the motion of the heat shall not interfere with the naturaltendencies of the steel molecules to place themselves in equilibriumwith the contactingiron 3 5 molecules and create a reciprocal attractionbetween the two metals. To accomplish this the piles should be firstheated so slowly that the heat can entirely penetrate the steel degreeby degree until the latter is partially, or

preferably entirely, molten, and then, secondly, the character of theheat should be changed,- and the iron envelope should be brought asrapidly as possible to a white welding-heat.

. The steel molecules will surrender a small por- 4 5 tion of theircarbon to the iron molecules with which they are thus brought into suchclose contact, and they will fuse and blend together so intimately thaton both sides of the line of contact and within a very limited space the0 change of nature from one metal to the other will shade down verygradually.

In practically carrying out my invention I place the piles in a goodironheating-furnace well heated, work with a closed damper, and heat soslowly that the heat is kept ata point which will not injure the iron,but will still penetrate into thecore of the steel degree by degree andreduce it to a molten condition. I thus reach the first step. The timerequired to do this will vary with the size of the piles and thecondition of the furnace, and it requires only the same kind ofexperience as that which enables a good heater to ascertain the amountof heat particular iron will bear. When this molten condition of thesteel is attained the secondstage commences, thedamper is raised, andthe piles are given ,as rapidly as possible all the heat which the ironin the piles will bear until it is brought to a high white welding-heat.When brought to this state and the piles are then subjected tocompression, either by hammer, rolls, or hydraulic pressure, the processis completed, and thefusion is made so perfect that it is impossible .toseparate the two metals at the point ofunion.

I prefer the use of rolls orhyd raulic pressure to the hammer, becausewith the first two, it thepiles are properly proportioned and the twometals areeachofuniform width and thickness throughout their entirelength and breadth, the distinct lines and character of both metals willpractically be maintained in uniform lines down to the smallest section.

A simple mode of making the piles or boxes is to shear paddled bars ofthe requisite length 85 and breadth for top and bottom pieces. Then onthe bottom piece are placed on edge two pieces, each one bent to adouble right angle, (this may be done as the bars come from the rolls,)sheared long enough to overlap, thus forming bottom, sides, and ends ofa box. In the center is then placed steel enough to till it, top placedon, and the box, wired, is ready for the furnace. The steel may be inone or many pieces, oxidized or not. The expansion of the 5 iron underheat will soon (if the puddled bars are rolled true) make the envelopeof iron suffieiently tight to protect the steel during heating and holdit when molten.

It will readily be understood that any re-'1oo quired specification forany use can be met. For instance, if the envelope is made of iron highin phosphorus and the steel is low in carbou, you have a hard surfacecombined with great strength, as required in rails, wagon-tires, andmany other uses. When very high tensile strength, combined with safetyunder hot or cold treatment, as well as in service, is required, I takea steel high in carbon and an iron very ductile and fibrous. Thesequalities are demanded in boiler-plates, ship-plates, bridge structures,and many other uses.

This product can be'worked and welded precisely as iron, and is as safein working or service as the best iron,because the iron envelope must bebroken fiber by fiber to cause fracture.

The great value of a product uniting the marked and distinctivelyvaluable quality of each metal, and so thoroughly fused as tobecomehomogeneousin structure, but preserving at the same time theirdistinctivelines, is so well known as to need no elaboration. Thedifliculty has been to produce it perfect and uniform both in result andquality, and ata cost. to make it commercially valuable. Therefore WhatI claim as new and forming my invention is- This'mode of heating pilesor boxes composed of a steel core of any shape, said core surrounded byan envelope of puddled or other ironviz., by first subjecting thesepiles to a low slow heat, such as will not injuriously afiect the ironuntil the heat penetrates the whole body of steel degree by degree untilit becomes partially, or preferably entirely, molten, and then, in thesecond place, changing the character of the heat, so as rapidly to bringthe iron envelope to a high white welding-heat, and then by compressioncompleting the process, and thus produein g an absolute fusion insteadof a weld of the two metalssubstantially for the purpose describedabove.

March 12, 1881.

QJNO. HALDEMAN.

Witnesses:

I. N. SEARs, J. H. WORTHINGTON.

